The　production　of　aluminium　oxide　from　coal　flay　ash,　an　aluminum-rich　and　silicate-based　solid　waste,　has　been　found　uneconomic,　particularly　due　to　the　great　challenge　for　impurity　removal.　The　present　study　proposes　a　new　process　to　recover　aluminum　oxide　from　coal　fly　ash　using　pressure　leaching　with　sulfuric　acid,　followed　by　crystallization　and　pyrolysis　of　potassium-alum.　The　thermodynamic　and　experimental　analyses　results　show　the　feasibility　of　obtaining　metallurgical-grade　aluminum　oxide　using　the　new　process,　with　low　reagent　and　energy　consumption.　In　the　process,　the　separation　of　aluminum　from　the　complicated　sulfate　leachate　can　be　achieved　efficiently.　The　excess　sulfuric　acid,　potassium　sulfate　and　oxy-sulfide　(obtained　from　pyrolysis)　can　all　be　recycled　for　reused.　The　comparisons　between　the　new　process　and　the　traditional　Bayer　process　indicate　that　the　new　process　for　aluminum　oxide　production　from　aluminum-rich　and　silicate-based　materials　has　a　wide　application.　©　2022,　China　Science　Publishing　&　Media　Ltd.　All　right　reserved.